diff options
Diffstat (limited to 'Documentation')
42 files changed, 585 insertions, 102 deletions
diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu index 206079d3bd5b..53755b2021ed 100644 --- a/Documentation/ABI/testing/sysfs-devices-system-cpu +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -511,6 +511,7 @@ Description: information about CPUs heterogeneity. What: /sys/devices/system/cpu/vulnerabilities /sys/devices/system/cpu/vulnerabilities/gather_data_sampling + /sys/devices/system/cpu/vulnerabilities/indirect_target_selection /sys/devices/system/cpu/vulnerabilities/itlb_multihit /sys/devices/system/cpu/vulnerabilities/l1tf /sys/devices/system/cpu/vulnerabilities/mds @@ -522,6 +523,7 @@ What: /sys/devices/system/cpu/vulnerabilities /sys/devices/system/cpu/vulnerabilities/spectre_v1 /sys/devices/system/cpu/vulnerabilities/spectre_v2 /sys/devices/system/cpu/vulnerabilities/srbds + /sys/devices/system/cpu/vulnerabilities/tsa /sys/devices/system/cpu/vulnerabilities/tsx_async_abort Date: January 2018 Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org> diff --git a/Documentation/ABI/testing/sysfs-driver-ufs b/Documentation/ABI/testing/sysfs-driver-ufs index 5fa6655aee84..16f17e91ee49 100644 --- a/Documentation/ABI/testing/sysfs-driver-ufs +++ b/Documentation/ABI/testing/sysfs-driver-ufs @@ -711,7 +711,7 @@ Description: This file shows the thin provisioning type. This is one of The file is read only. -What: /sys/class/scsi_device/*/device/unit_descriptor/physical_memory_resourse_count +What: /sys/class/scsi_device/*/device/unit_descriptor/physical_memory_resource_count Date: February 2018 Contact: Stanislav Nijnikov <stanislav.nijnikov@wdc.com> Description: This file shows the total physical memory resources. This is diff --git a/Documentation/admin-guide/hw-vuln/index.rst b/Documentation/admin-guide/hw-vuln/index.rst index ff0b440ef2dc..d2caa390395e 100644 --- a/Documentation/admin-guide/hw-vuln/index.rst +++ b/Documentation/admin-guide/hw-vuln/index.rst @@ -22,3 +22,4 @@ are configurable at compile, boot or run time. srso gather_data_sampling reg-file-data-sampling + indirect-target-selection diff --git a/Documentation/admin-guide/hw-vuln/indirect-target-selection.rst b/Documentation/admin-guide/hw-vuln/indirect-target-selection.rst new file mode 100644 index 000000000000..d9ca64108d23 --- /dev/null +++ b/Documentation/admin-guide/hw-vuln/indirect-target-selection.rst @@ -0,0 +1,168 @@ +.. SPDX-License-Identifier: GPL-2.0 + +Indirect Target Selection (ITS) +=============================== + +ITS is a vulnerability in some Intel CPUs that support Enhanced IBRS and were +released before Alder Lake. ITS may allow an attacker to control the prediction +of indirect branches and RETs located in the lower half of a cacheline. + +ITS is assigned CVE-2024-28956 with a CVSS score of 4.7 (Medium). + +Scope of Impact +--------------- +- **eIBRS Guest/Host Isolation**: Indirect branches in KVM/kernel may still be + predicted with unintended target corresponding to a branch in the guest. + +- **Intra-Mode BTI**: In-kernel training such as through cBPF or other native + gadgets. + +- **Indirect Branch Prediction Barrier (IBPB)**: After an IBPB, indirect + branches may still be predicted with targets corresponding to direct branches + executed prior to the IBPB. This is fixed by the IPU 2025.1 microcode, which + should be available via distro updates. Alternatively microcode can be + obtained from Intel's github repository [#f1]_. + +Affected CPUs +------------- +Below is the list of ITS affected CPUs [#f2]_ [#f3]_: + + ======================== ============ ==================== =============== + Common name Family_Model eIBRS Intra-mode BTI + Guest/Host Isolation + ======================== ============ ==================== =============== + SKYLAKE_X (step >= 6) 06_55H Affected Affected + ICELAKE_X 06_6AH Not affected Affected + ICELAKE_D 06_6CH Not affected Affected + ICELAKE_L 06_7EH Not affected Affected + TIGERLAKE_L 06_8CH Not affected Affected + TIGERLAKE 06_8DH Not affected Affected + KABYLAKE_L (step >= 12) 06_8EH Affected Affected + KABYLAKE (step >= 13) 06_9EH Affected Affected + COMETLAKE 06_A5H Affected Affected + COMETLAKE_L 06_A6H Affected Affected + ROCKETLAKE 06_A7H Not affected Affected + ======================== ============ ==================== =============== + +- All affected CPUs enumerate Enhanced IBRS feature. +- IBPB isolation is affected on all ITS affected CPUs, and need a microcode + update for mitigation. +- None of the affected CPUs enumerate BHI_CTRL which was introduced in Golden + Cove (Alder Lake and Sapphire Rapids). This can help guests to determine the + host's affected status. +- Intel Atom CPUs are not affected by ITS. + +Mitigation +---------- +As only the indirect branches and RETs that have their last byte of instruction +in the lower half of the cacheline are vulnerable to ITS, the basic idea behind +the mitigation is to not allow indirect branches in the lower half. + +This is achieved by relying on existing retpoline support in the kernel, and in +compilers. ITS-vulnerable retpoline sites are runtime patched to point to newly +added ITS-safe thunks. These safe thunks consists of indirect branch in the +second half of the cacheline. Not all retpoline sites are patched to thunks, if +a retpoline site is evaluated to be ITS-safe, it is replaced with an inline +indirect branch. + +Dynamic thunks +~~~~~~~~~~~~~~ +From a dynamically allocated pool of safe-thunks, each vulnerable site is +replaced with a new thunk, such that they get a unique address. This could +improve the branch prediction accuracy. Also, it is a defense-in-depth measure +against aliasing. + +Note, for simplicity, indirect branches in eBPF programs are always replaced +with a jump to a static thunk in __x86_indirect_its_thunk_array. If required, +in future this can be changed to use dynamic thunks. + +All vulnerable RETs are replaced with a static thunk, they do not use dynamic +thunks. This is because RETs get their prediction from RSB mostly that does not +depend on source address. RETs that underflow RSB may benefit from dynamic +thunks. But, RETs significantly outnumber indirect branches, and any benefit +from a unique source address could be outweighed by the increased icache +footprint and iTLB pressure. + +Retpoline +~~~~~~~~~ +Retpoline sequence also mitigates ITS-unsafe indirect branches. For this +reason, when retpoline is enabled, ITS mitigation only relocates the RETs to +safe thunks. Unless user requested the RSB-stuffing mitigation. + +RSB Stuffing +~~~~~~~~~~~~ +RSB-stuffing via Call Depth Tracking is a mitigation for Retbleed RSB-underflow +attacks. And it also mitigates RETs that are vulnerable to ITS. + +Mitigation in guests +^^^^^^^^^^^^^^^^^^^^ +All guests deploy ITS mitigation by default, irrespective of eIBRS enumeration +and Family/Model of the guest. This is because eIBRS feature could be hidden +from a guest. One exception to this is when a guest enumerates BHI_DIS_S, which +indicates that the guest is running on an unaffected host. + +To prevent guests from unnecessarily deploying the mitigation on unaffected +platforms, Intel has defined ITS_NO bit(62) in MSR IA32_ARCH_CAPABILITIES. When +a guest sees this bit set, it should not enumerate the ITS bug. Note, this bit +is not set by any hardware, but is **intended for VMMs to synthesize** it for +guests as per the host's affected status. + +Mitigation options +^^^^^^^^^^^^^^^^^^ +The ITS mitigation can be controlled using the "indirect_target_selection" +kernel parameter. The available options are: + + ======== =================================================================== + on (default) Deploy the "Aligned branch/return thunks" mitigation. + If spectre_v2 mitigation enables retpoline, aligned-thunks are only + deployed for the affected RET instructions. Retpoline mitigates + indirect branches. + + off Disable ITS mitigation. + + vmexit Equivalent to "=on" if the CPU is affected by guest/host isolation + part of ITS. Otherwise, mitigation is not deployed. This option is + useful when host userspace is not in the threat model, and only + attacks from guest to host are considered. + + stuff Deploy RSB-fill mitigation when retpoline is also deployed. + Otherwise, deploy the default mitigation. When retpoline mitigation + is enabled, RSB-stuffing via Call-Depth-Tracking also mitigates + ITS. + + force Force the ITS bug and deploy the default mitigation. + ======== =================================================================== + +Sysfs reporting +--------------- + +The sysfs file showing ITS mitigation status is: + + /sys/devices/system/cpu/vulnerabilities/indirect_target_selection + +Note, microcode mitigation status is not reported in this file. + +The possible values in this file are: + +.. list-table:: + + * - Not affected + - The processor is not vulnerable. + * - Vulnerable + - System is vulnerable and no mitigation has been applied. + * - Vulnerable, KVM: Not affected + - System is vulnerable to intra-mode BTI, but not affected by eIBRS + guest/host isolation. + * - Mitigation: Aligned branch/return thunks + - The mitigation is enabled, affected indirect branches and RETs are + relocated to safe thunks. + * - Mitigation: Retpolines, Stuffing RSB + - The mitigation is enabled using retpoline and RSB stuffing. + +References +---------- +.. [#f1] Microcode repository - https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files + +.. [#f2] Affected Processors list - https://www.intel.com/content/www/us/en/developer/topic-technology/software-security-guidance/processors-affected-consolidated-product-cpu-model.html + +.. [#f3] Affected Processors list (machine readable) - https://github.com/intel/Intel-affected-processor-list diff --git a/Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst b/Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst index 1302fd1b55e8..6dba18dbb9ab 100644 --- a/Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst +++ b/Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst @@ -157,9 +157,7 @@ This is achieved by using the otherwise unused and obsolete VERW instruction in combination with a microcode update. The microcode clears the affected CPU buffers when the VERW instruction is executed. -Kernel reuses the MDS function to invoke the buffer clearing: - - mds_clear_cpu_buffers() +Kernel does the buffer clearing with x86_clear_cpu_buffers(). On MDS affected CPUs, the kernel already invokes CPU buffer clear on kernel/userspace, hypervisor/guest and C-state (idle) transitions. No diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index d401577b5a6a..f402bbaccc8a 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2149,6 +2149,23 @@ different crypto accelerators. This option can be used to achieve best performance for particular HW. + indirect_target_selection= [X86,Intel] Mitigation control for Indirect + Target Selection(ITS) bug in Intel CPUs. Updated + microcode is also required for a fix in IBPB. + + on: Enable mitigation (default). + off: Disable mitigation. + force: Force the ITS bug and deploy default + mitigation. + vmexit: Only deploy mitigation if CPU is affected by + guest/host isolation part of ITS. + stuff: Deploy RSB-fill mitigation when retpoline is + also deployed. Otherwise, deploy the default + mitigation. + + For details see: + Documentation/admin-guide/hw-vuln/indirect-target-selection.rst + init= [KNL] Format: <full_path> Run specified binary instead of /sbin/init as init @@ -3028,6 +3045,8 @@ * max_sec_lba48: Set or clear transfer size limit to 65535 sectors. + * external: Mark port as external (hotplug-capable). + * [no]lpm: Enable or disable link power management. * [no]setxfer: Indicate if transfer speed mode setting @@ -3508,6 +3527,7 @@ expose users to several CPU vulnerabilities. Equivalent to: if nokaslr then kpti=0 [ARM64] gather_data_sampling=off [X86] + indirect_target_selection=off [X86] kvm.nx_huge_pages=off [X86] l1tf=off [X86] mds=off [X86] @@ -6241,6 +6261,8 @@ Selecting 'on' will also enable the mitigation against user space to user space task attacks. + Selecting specific mitigation does not force enable + user mitigations. Selecting 'off' will disable both the kernel and the user space protections. @@ -6971,6 +6993,19 @@ having this key zero'ed is acceptable. E.g. in testing scenarios. + tsa= [X86] Control mitigation for Transient Scheduler + Attacks on AMD CPUs. Search the following in your + favourite search engine for more details: + + "Technical guidance for mitigating transient scheduler + attacks". + + off - disable the mitigation + on - enable the mitigation (default) + user - mitigate only user/kernel transitions + vm - mitigate only guest/host transitions + + tsc= Disable clocksource stability checks for TSC. Format: <string> [x86] reliable: mark tsc clocksource as reliable, this diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index f8bc1630eba0..fa21cdd610b2 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -212,6 +212,17 @@ pid>/``). This value defaults to 0. +core_sort_vma +============= + +The default coredump writes VMAs in address order. By setting +``core_sort_vma`` to 1, VMAs will be written from smallest size +to largest size. This is known to break at least elfutils, but +can be handy when dealing with very large (and truncated) +coredumps where the more useful debugging details are included +in the smaller VMAs. + + core_uses_pid ============= diff --git a/Documentation/arch/arm64/booting.rst b/Documentation/arch/arm64/booting.rst index b57776a68f15..15bcd1b4003a 100644 --- a/Documentation/arch/arm64/booting.rst +++ b/Documentation/arch/arm64/booting.rst @@ -285,6 +285,12 @@ Before jumping into the kernel, the following conditions must be met: - SCR_EL3.FGTEn (bit 27) must be initialised to 0b1. + For CPUs with the Fine Grained Traps 2 (FEAT_FGT2) extension present: + + - If EL3 is present and the kernel is entered at EL2: + + - SCR_EL3.FGTEn2 (bit 59) must be initialised to 0b1. + For CPUs with support for HCRX_EL2 (FEAT_HCX) present: - If EL3 is present and the kernel is entered at EL2: @@ -379,6 +385,22 @@ Before jumping into the kernel, the following conditions must be met: - SMCR_EL2.EZT0 (bit 30) must be initialised to 0b1. + For CPUs with the Performance Monitors Extension (FEAT_PMUv3p9): + + - If EL3 is present: + + - MDCR_EL3.EnPM2 (bit 7) must be initialised to 0b1. + + - If the kernel is entered at EL1 and EL2 is present: + + - HDFGRTR2_EL2.nPMICNTR_EL0 (bit 2) must be initialised to 0b1. + - HDFGRTR2_EL2.nPMICFILTR_EL0 (bit 3) must be initialised to 0b1. + - HDFGRTR2_EL2.nPMUACR_EL1 (bit 4) must be initialised to 0b1. + + - HDFGWTR2_EL2.nPMICNTR_EL0 (bit 2) must be initialised to 0b1. + - HDFGWTR2_EL2.nPMICFILTR_EL0 (bit 3) must be initialised to 0b1. + - HDFGWTR2_EL2.nPMUACR_EL1 (bit 4) must be initialised to 0b1. + For CPUs with Memory Copy and Memory Set instructions (FEAT_MOPS): - If the kernel is entered at EL1 and EL2 is present: diff --git a/Documentation/arch/x86/mds.rst b/Documentation/arch/x86/mds.rst index 5a2e6c0ef04a..3518671e1a85 100644 --- a/Documentation/arch/x86/mds.rst +++ b/Documentation/arch/x86/mds.rst @@ -93,7 +93,7 @@ enters a C-state. The kernel provides a function to invoke the buffer clearing: - mds_clear_cpu_buffers() + x86_clear_cpu_buffers() Also macro CLEAR_CPU_BUFFERS can be used in ASM late in exit-to-user path. Other than CFLAGS.ZF, this macro doesn't clobber any registers. @@ -185,9 +185,9 @@ Mitigation points idle clearing would be a window dressing exercise and is therefore not activated. - The invocation is controlled by the static key mds_idle_clear which is - switched depending on the chosen mitigation mode and the SMT state of - the system. + The invocation is controlled by the static key cpu_buf_idle_clear which is + switched depending on the chosen mitigation mode and the SMT state of the + system. The buffer clear is only invoked before entering the C-State to prevent that stale data from the idling CPU from spilling to the Hyper-Thread diff --git a/Documentation/bpf/bpf_devel_QA.rst b/Documentation/bpf/bpf_devel_QA.rst index de27e1620821..0acb4c9b8d90 100644 --- a/Documentation/bpf/bpf_devel_QA.rst +++ b/Documentation/bpf/bpf_devel_QA.rst @@ -382,6 +382,14 @@ In case of new BPF instructions, once the changes have been accepted into the Linux kernel, please implement support into LLVM's BPF back end. See LLVM_ section below for further information. +Q: What "BPF_INTERNAL" symbol namespace is for? +----------------------------------------------- +A: Symbols exported as BPF_INTERNAL can only be used by BPF infrastructure +like preload kernel modules with light skeleton. Most symbols outside +of BPF_INTERNAL are not expected to be used by code outside of BPF either. +Symbols may lack the designation because they predate the namespaces, +or due to an oversight. + Stable submission ================= diff --git a/Documentation/bpf/map_hash.rst b/Documentation/bpf/map_hash.rst index d2343952f2cb..8606bf958a8c 100644 --- a/Documentation/bpf/map_hash.rst +++ b/Documentation/bpf/map_hash.rst @@ -233,10 +233,16 @@ attempts in order to enforce the LRU property which have increasing impacts on other CPUs involved in the following operation attempts: - Attempt to use CPU-local state to batch operations -- Attempt to fetch free nodes from global lists +- Attempt to fetch ``target_free`` free nodes from global lists - Attempt to pull any node from a global list and remove it from the hashmap - Attempt to pull any node from any CPU's list and remove it from the hashmap +The number of nodes to borrow from the global list in a batch, ``target_free``, +depends on the size of the map. Larger batch size reduces lock contention, but +may also exhaust the global structure. The value is computed at map init to +avoid exhaustion, by limiting aggregate reservation by all CPUs to half the map +size. With a minimum of a single element and maximum budget of 128 at a time. + This algorithm is described visually in the following diagram. See the description in commit 3a08c2fd7634 ("bpf: LRU List") for a full explanation of the corresponding operations: diff --git a/Documentation/bpf/map_lru_hash_update.dot b/Documentation/bpf/map_lru_hash_update.dot index a0fee349d29c..ab10058f5b79 100644 --- a/Documentation/bpf/map_lru_hash_update.dot +++ b/Documentation/bpf/map_lru_hash_update.dot @@ -35,18 +35,18 @@ digraph { fn_bpf_lru_list_pop_free_to_local [shape=rectangle,fillcolor=2, label="Flush local pending, Rotate Global list, move - LOCAL_FREE_TARGET + target_free from global -> local"] // Also corresponds to: // fn__local_list_flush() // fn_bpf_lru_list_rotate() fn___bpf_lru_node_move_to_free[shape=diamond,fillcolor=2, - label="Able to free\nLOCAL_FREE_TARGET\nnodes?"] + label="Able to free\ntarget_free\nnodes?"] fn___bpf_lru_list_shrink_inactive [shape=rectangle,fillcolor=3, label="Shrink inactive list up to remaining - LOCAL_FREE_TARGET + target_free (global LRU -> local)"] fn___bpf_lru_list_shrink [shape=diamond,fillcolor=2, label="> 0 entries in\nlocal free list?"] diff --git a/Documentation/core-api/symbol-namespaces.rst b/Documentation/core-api/symbol-namespaces.rst index d1154eb43810..cca94469fa41 100644 --- a/Documentation/core-api/symbol-namespaces.rst +++ b/Documentation/core-api/symbol-namespaces.rst @@ -28,6 +28,9 @@ kernel. As of today, modules that make use of symbols exported into namespaces, are required to import the namespace. Otherwise the kernel will, depending on its configuration, reject loading the module or warn about a missing import. +Additionally, it is possible to put symbols into a module namespace, strictly +limiting which modules are allowed to use these symbols. + 2. How to define Symbol Namespaces ================================== @@ -84,6 +87,22 @@ unit as preprocessor statement. The above example would then read:: within the corresponding compilation unit before any EXPORT_SYMBOL macro is used. +2.3 Using the EXPORT_SYMBOL_GPL_FOR_MODULES() macro +=================================================== + +Symbols exported using this macro are put into a module namespace. This +namespace cannot be imported. + +The macro takes a comma separated list of module names, allowing only those +modules to access this symbol. Simple tail-globs are supported. + +For example: + + EXPORT_SYMBOL_GPL_FOR_MODULES(preempt_notifier_inc, "kvm,kvm-*") + +will limit usage of this symbol to modules whoes name matches the given +patterns. + 3. How to use Symbols exported in Namespaces ============================================ @@ -155,3 +174,6 @@ in-tree modules:: You can also run nsdeps for external module builds. A typical usage is:: $ make -C <path_to_kernel_src> M=$PWD nsdeps + +Note: it will happily generate an import statement for the module namespace; +which will not work and generates build and runtime failures. diff --git a/Documentation/devicetree/bindings/arm/qcom,coresight-tpda.yaml b/Documentation/devicetree/bindings/arm/qcom,coresight-tpda.yaml index 76163abed655..5ed40f21b8eb 100644 --- a/Documentation/devicetree/bindings/arm/qcom,coresight-tpda.yaml +++ b/Documentation/devicetree/bindings/arm/qcom,coresight-tpda.yaml @@ -55,8 +55,7 @@ properties: - const: arm,primecell reg: - minItems: 1 - maxItems: 2 + maxItems: 1 clocks: maxItems: 1 diff --git a/Documentation/devicetree/bindings/arm/qcom,coresight-tpdm.yaml b/Documentation/devicetree/bindings/arm/qcom,coresight-tpdm.yaml index 8eec07d9d454..07d21a3617f5 100644 --- a/Documentation/devicetree/bindings/arm/qcom,coresight-tpdm.yaml +++ b/Documentation/devicetree/bindings/arm/qcom,coresight-tpdm.yaml @@ -41,8 +41,7 @@ properties: - const: arm,primecell reg: - minItems: 1 - maxItems: 2 + maxItems: 1 qcom,dsb-element-bits: description: diff --git a/Documentation/devicetree/bindings/i2c/nvidia,tegra20-i2c.yaml b/Documentation/devicetree/bindings/i2c/nvidia,tegra20-i2c.yaml index b57ae6963e62..6b6f6762d122 100644 --- a/Documentation/devicetree/bindings/i2c/nvidia,tegra20-i2c.yaml +++ b/Documentation/devicetree/bindings/i2c/nvidia,tegra20-i2c.yaml @@ -97,7 +97,10 @@ properties: resets: items: - - description: module reset + - description: + Module reset. This property is optional for controllers in Tegra194, + Tegra234 etc where an internal software reset is available as an + alternative. reset-names: items: @@ -116,6 +119,13 @@ properties: - const: rx - const: tx +required: + - compatible + - reg + - interrupts + - clocks + - clock-names + allOf: - $ref: /schemas/i2c/i2c-controller.yaml - if: @@ -169,6 +179,18 @@ allOf: properties: power-domains: false + - if: + not: + properties: + compatible: + contains: + enum: + - nvidia,tegra194-i2c + then: + required: + - resets + - reset-names + unevaluatedProperties: false examples: diff --git a/Documentation/devicetree/bindings/media/i2c/st,st-mipid02.yaml b/Documentation/devicetree/bindings/media/i2c/st,st-mipid02.yaml index b68141264c0e..4d40e75b4e1e 100644 --- a/Documentation/devicetree/bindings/media/i2c/st,st-mipid02.yaml +++ b/Documentation/devicetree/bindings/media/i2c/st,st-mipid02.yaml @@ -71,7 +71,7 @@ properties: description: Any lane can be inverted or not. minItems: 1 - maxItems: 2 + maxItems: 3 required: - data-lanes diff --git a/Documentation/devicetree/bindings/net/can/renesas,rcar-canfd.yaml b/Documentation/devicetree/bindings/net/can/renesas,rcar-canfd.yaml index 7c5ac5d2e880..f6884f6e59e7 100644 --- a/Documentation/devicetree/bindings/net/can/renesas,rcar-canfd.yaml +++ b/Documentation/devicetree/bindings/net/can/renesas,rcar-canfd.yaml @@ -170,7 +170,7 @@ allOf: const: renesas,r8a779h0-canfd then: patternProperties: - "^channel[5-7]$": false + "^channel[4-7]$": false else: if: not: diff --git a/Documentation/devicetree/bindings/phy/fsl,imx8mq-usb-phy.yaml b/Documentation/devicetree/bindings/phy/fsl,imx8mq-usb-phy.yaml index dc3a3f709fea..bac4d0b51d8a 100644 --- a/Documentation/devicetree/bindings/phy/fsl,imx8mq-usb-phy.yaml +++ b/Documentation/devicetree/bindings/phy/fsl,imx8mq-usb-phy.yaml @@ -58,8 +58,7 @@ properties: fsl,phy-tx-vboost-level-microvolt: description: Adjust the boosted transmit launch pk-pk differential amplitude - minimum: 880 - maximum: 1120 + enum: [844, 1008, 1156] fsl,phy-comp-dis-tune-percent: description: diff --git a/Documentation/devicetree/bindings/pwm/adi,axi-pwmgen.yaml b/Documentation/devicetree/bindings/pwm/adi,axi-pwmgen.yaml index ec6115d3796b..5575c58357d6 100644 --- a/Documentation/devicetree/bindings/pwm/adi,axi-pwmgen.yaml +++ b/Documentation/devicetree/bindings/pwm/adi,axi-pwmgen.yaml @@ -27,22 +27,31 @@ properties: maxItems: 1 "#pwm-cells": - const: 2 + const: 3 clocks: - maxItems: 1 + minItems: 1 + maxItems: 2 + + clock-names: + minItems: 1 + items: + - const: axi + - const: ext required: - reg - clocks + - clock-names unevaluatedProperties: false examples: - | pwm@44b00000 { - compatible = "adi,axi-pwmgen-2.00.a"; - reg = <0x44b00000 0x1000>; - clocks = <&spi_clk>; - #pwm-cells = <2>; + compatible = "adi,axi-pwmgen-2.00.a"; + reg = <0x44b00000 0x1000>; + clocks = <&fpga_clk>, <&spi_clk>; + clock-names = "axi", "ext"; + #pwm-cells = <3>; }; diff --git a/Documentation/devicetree/bindings/pwm/brcm,bcm7038-pwm.yaml b/Documentation/devicetree/bindings/pwm/brcm,bcm7038-pwm.yaml index 119de3d7f9dd..44548a9da158 100644 --- a/Documentation/devicetree/bindings/pwm/brcm,bcm7038-pwm.yaml +++ b/Documentation/devicetree/bindings/pwm/brcm,bcm7038-pwm.yaml @@ -35,8 +35,8 @@ additionalProperties: false examples: - | pwm: pwm@f0408000 { - compatible = "brcm,bcm7038-pwm"; - reg = <0xf0408000 0x28>; - #pwm-cells = <2>; - clocks = <&upg_fixed>; + compatible = "brcm,bcm7038-pwm"; + reg = <0xf0408000 0x28>; + #pwm-cells = <2>; + clocks = <&upg_fixed>; }; diff --git a/Documentation/devicetree/bindings/pwm/brcm,kona-pwm.yaml b/Documentation/devicetree/bindings/pwm/brcm,kona-pwm.yaml index e86c8053b366..fd785da5d3d7 100644 --- a/Documentation/devicetree/bindings/pwm/brcm,kona-pwm.yaml +++ b/Documentation/devicetree/bindings/pwm/brcm,kona-pwm.yaml @@ -43,9 +43,9 @@ examples: #include <dt-bindings/clock/bcm281xx.h> pwm@3e01a000 { - compatible = "brcm,bcm11351-pwm", "brcm,kona-pwm"; - reg = <0x3e01a000 0xcc>; - clocks = <&slave_ccu BCM281XX_SLAVE_CCU_PWM>; - #pwm-cells = <3>; + compatible = "brcm,bcm11351-pwm", "brcm,kona-pwm"; + reg = <0x3e01a000 0xcc>; + clocks = <&slave_ccu BCM281XX_SLAVE_CCU_PWM>; + #pwm-cells = <3>; }; ... diff --git a/Documentation/devicetree/bindings/regulator/mediatek,mt6357-regulator.yaml b/Documentation/devicetree/bindings/regulator/mediatek,mt6357-regulator.yaml index 6327bb2f6ee0..698266c09e25 100644 --- a/Documentation/devicetree/bindings/regulator/mediatek,mt6357-regulator.yaml +++ b/Documentation/devicetree/bindings/regulator/mediatek,mt6357-regulator.yaml @@ -33,7 +33,7 @@ patternProperties: "^ldo-v(camio18|aud28|aux18|io18|io28|rf12|rf18|cn18|cn28|fe28)$": type: object - $ref: fixed-regulator.yaml# + $ref: regulator.yaml# unevaluatedProperties: false description: Properties for single fixed LDO regulator. @@ -112,7 +112,6 @@ examples: regulator-enable-ramp-delay = <220>; }; mt6357_vfe28_reg: ldo-vfe28 { - compatible = "regulator-fixed"; regulator-name = "vfe28"; regulator-min-microvolt = <2800000>; regulator-max-microvolt = <2800000>; @@ -125,14 +124,12 @@ examples: regulator-enable-ramp-delay = <110>; }; mt6357_vrf18_reg: ldo-vrf18 { - compatible = "regulator-fixed"; regulator-name = "vrf18"; regulator-min-microvolt = <1800000>; regulator-max-microvolt = <1800000>; regulator-enable-ramp-delay = <110>; }; mt6357_vrf12_reg: ldo-vrf12 { - compatible = "regulator-fixed"; regulator-name = "vrf12"; regulator-min-microvolt = <1200000>; regulator-max-microvolt = <1200000>; @@ -157,14 +154,12 @@ examples: regulator-enable-ramp-delay = <264>; }; mt6357_vcn28_reg: ldo-vcn28 { - compatible = "regulator-fixed"; regulator-name = "vcn28"; regulator-min-microvolt = <2800000>; regulator-max-microvolt = <2800000>; regulator-enable-ramp-delay = <264>; }; mt6357_vcn18_reg: ldo-vcn18 { - compatible = "regulator-fixed"; regulator-name = "vcn18"; regulator-min-microvolt = <1800000>; regulator-max-microvolt = <1800000>; @@ -183,7 +178,6 @@ examples: regulator-enable-ramp-delay = <264>; }; mt6357_vcamio_reg: ldo-vcamio18 { - compatible = "regulator-fixed"; regulator-name = "vcamio"; regulator-min-microvolt = <1800000>; regulator-max-microvolt = <1800000>; @@ -212,28 +206,24 @@ examples: regulator-always-on; }; mt6357_vaux18_reg: ldo-vaux18 { - compatible = "regulator-fixed"; regulator-name = "vaux18"; regulator-min-microvolt = <1800000>; regulator-max-microvolt = <1800000>; regulator-enable-ramp-delay = <264>; }; mt6357_vaud28_reg: ldo-vaud28 { - compatible = "regulator-fixed"; regulator-name = "vaud28"; regulator-min-microvolt = <2800000>; regulator-max-microvolt = <2800000>; regulator-enable-ramp-delay = <264>; }; mt6357_vio28_reg: ldo-vio28 { - compatible = "regulator-fixed"; regulator-name = "vio28"; regulator-min-microvolt = <2800000>; regulator-max-microvolt = <2800000>; regulator-enable-ramp-delay = <264>; }; mt6357_vio18_reg: ldo-vio18 { - compatible = "regulator-fixed"; regulator-name = "vio18"; regulator-min-microvolt = <1800000>; regulator-max-microvolt = <1800000>; diff --git a/Documentation/devicetree/bindings/serial/8250.yaml b/Documentation/devicetree/bindings/serial/8250.yaml index 692aa05500fd..6ba0325039be 100644 --- a/Documentation/devicetree/bindings/serial/8250.yaml +++ b/Documentation/devicetree/bindings/serial/8250.yaml @@ -45,7 +45,7 @@ allOf: - ns16550 - ns16550a then: - anyOf: + oneOf: - required: [ clock-frequency ] - required: [ clocks ] diff --git a/Documentation/devicetree/bindings/soc/fsl/fsl,ls1028a-reset.yaml b/Documentation/devicetree/bindings/soc/fsl/fsl,ls1028a-reset.yaml index 31295be91013..234089b5954d 100644 --- a/Documentation/devicetree/bindings/soc/fsl/fsl,ls1028a-reset.yaml +++ b/Documentation/devicetree/bindings/soc/fsl/fsl,ls1028a-reset.yaml @@ -7,7 +7,7 @@ $schema: http://devicetree.org/meta-schemas/core.yaml# title: Freescale Layerscape Reset Registers Module maintainers: - - Frank Li + - Frank Li <Frank.Li@nxp.com> description: Reset Module includes chip reset, service processor control and Reset Control diff --git a/Documentation/devicetree/bindings/soc/fsl/fsl,qman-fqd.yaml b/Documentation/devicetree/bindings/soc/fsl/fsl,qman-fqd.yaml index de0b4ae740ff..a975bce59975 100644 --- a/Documentation/devicetree/bindings/soc/fsl/fsl,qman-fqd.yaml +++ b/Documentation/devicetree/bindings/soc/fsl/fsl,qman-fqd.yaml @@ -50,7 +50,7 @@ required: - compatible allOf: - - $ref: reserved-memory.yaml + - $ref: /schemas/reserved-memory/reserved-memory.yaml unevaluatedProperties: false @@ -61,7 +61,7 @@ examples: #size-cells = <2>; qman-fqd { - compatible = "shared-dma-pool"; + compatible = "fsl,qman-fqd"; size = <0 0x400000>; alignment = <0 0x400000>; no-map; diff --git a/Documentation/devicetree/bindings/usb/cypress,hx3.yaml b/Documentation/devicetree/bindings/usb/cypress,hx3.yaml index e44e88d993d0..e802e9ac975b 100644 --- a/Documentation/devicetree/bindings/usb/cypress,hx3.yaml +++ b/Documentation/devicetree/bindings/usb/cypress,hx3.yaml @@ -14,9 +14,22 @@ allOf: properties: compatible: - enum: - - usb4b4,6504 - - usb4b4,6506 + oneOf: + - enum: + - usb4b4,6504 + - usb4b4,6506 + - items: + - enum: + - usb4b4,6500 + - usb4b4,6508 + - const: usb4b4,6504 + - items: + - enum: + - usb4b4,6502 + - usb4b4,6503 + - usb4b4,6507 + - usb4b4,650a + - const: usb4b4,6506 reg: true diff --git a/Documentation/devicetree/bindings/vendor-prefixes.yaml b/Documentation/devicetree/bindings/vendor-prefixes.yaml index fbfce9b4ae6b..af9a8d43b247 100644 --- a/Documentation/devicetree/bindings/vendor-prefixes.yaml +++ b/Documentation/devicetree/bindings/vendor-prefixes.yaml @@ -581,6 +581,8 @@ patternProperties: description: GlobalTop Technology, Inc. "^gmt,.*": description: Global Mixed-mode Technology, Inc. + "^gocontroll,.*": + description: GOcontroll Modular Embedded Electronics B.V. "^goldelico,.*": description: Golden Delicious Computers GmbH & Co. KG "^goodix,.*": @@ -844,6 +846,8 @@ patternProperties: description: Linux-specific binding "^linx,.*": description: Linx Technologies + "^liontron,.*": + description: Shenzhen Liontron Technology Co., Ltd "^liteon,.*": description: LITE-ON Technology Corp. "^litex,.*": diff --git a/Documentation/driver-api/serial/driver.rst b/Documentation/driver-api/serial/driver.rst index 84b43061c11b..60434f2b0286 100644 --- a/Documentation/driver-api/serial/driver.rst +++ b/Documentation/driver-api/serial/driver.rst @@ -103,4 +103,4 @@ Some helpers are provided in order to set/get modem control lines via GPIO. .. kernel-doc:: drivers/tty/serial/serial_mctrl_gpio.c :identifiers: mctrl_gpio_init mctrl_gpio_free mctrl_gpio_to_gpiod mctrl_gpio_set mctrl_gpio_get mctrl_gpio_enable_ms - mctrl_gpio_disable_ms + mctrl_gpio_disable_ms_sync mctrl_gpio_disable_ms_no_sync diff --git a/Documentation/firmware-guide/acpi/dsd/data-node-references.rst b/Documentation/firmware-guide/acpi/dsd/data-node-references.rst index 8d8b53e96bcf..ccb4b153e6f2 100644 --- a/Documentation/firmware-guide/acpi/dsd/data-node-references.rst +++ b/Documentation/firmware-guide/acpi/dsd/data-node-references.rst @@ -12,11 +12,14 @@ ACPI in general allows referring to device objects in the tree only. Hierarchical data extension nodes may not be referred to directly, hence this document defines a scheme to implement such references. -A reference consist of the device object name followed by one or more -hierarchical data extension [dsd-guide] keys. Specifically, the hierarchical -data extension node which is referred to by the key shall lie directly under -the parent object i.e. either the device object or another hierarchical data -extension node. +A reference to a _DSD hierarchical data node is a string consisting of a +device object reference followed by a dot (".") and a relative path to a data +node object. Do not use non-string references as this will produce a copy of +the hierarchical data node, not a reference! + +The hierarchical data extension node which is referred to shall be located +directly under its parent object i.e. either the device object or another +hierarchical data extension node [dsd-guide]. The keys in the hierarchical data nodes shall consist of the name of the node, "@" character and the number of the node in hexadecimal notation (without pre- @@ -33,11 +36,9 @@ extension key. Example ======= -In the ASL snippet below, the "reference" _DSD property contains a -device object reference to DEV0 and under that device object, a -hierarchical data extension key "node@1" referring to the NOD1 object -and lastly, a hierarchical data extension key "anothernode" referring to -the ANOD object which is also the final target node of the reference. +In the ASL snippet below, the "reference" _DSD property contains a string +reference to a hierarchical data extension node ANOD under DEV0 under the parent +of DEV1. ANOD is also the final target node of the reference. :: Device (DEV0) @@ -76,10 +77,7 @@ the ANOD object which is also the final target node of the reference. Name (_DSD, Package () { ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), Package () { - Package () { - "reference", Package () { - ^DEV0, "node@1", "anothernode" - } + Package () { "reference", "^DEV0.ANOD" } }, } }) diff --git a/Documentation/firmware-guide/acpi/dsd/graph.rst b/Documentation/firmware-guide/acpi/dsd/graph.rst index b9dbfc73ed25..d6ae5ffa748c 100644 --- a/Documentation/firmware-guide/acpi/dsd/graph.rst +++ b/Documentation/firmware-guide/acpi/dsd/graph.rst @@ -66,12 +66,9 @@ of that port shall be zero. Similarly, if a port may only have a single endpoint, the number of that endpoint shall be zero. The endpoint reference uses property extension with "remote-endpoint" property -name followed by a reference in the same package. Such references consist of -the remote device reference, the first package entry of the port data extension -reference under the device and finally the first package entry of the endpoint -data extension reference under the port. Individual references thus appear as:: +name followed by a string reference in the same package. [data-node-ref]:: - Package() { device, "port@X", "endpoint@Y" } + "device.datanode" In the above example, "X" is the number of the port and "Y" is the number of the endpoint. @@ -109,7 +106,7 @@ A simple example of this is show below:: ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), Package () { Package () { "reg", 0 }, - Package () { "remote-endpoint", Package() { \_SB.PCI0.ISP, "port@4", "endpoint@0" } }, + Package () { "remote-endpoint", "\\_SB.PCI0.ISP.EP40" }, } }) } @@ -141,7 +138,7 @@ A simple example of this is show below:: ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), Package () { Package () { "reg", 0 }, - Package () { "remote-endpoint", Package () { \_SB.PCI0.I2C2.CAM0, "port@0", "endpoint@0" } }, + Package () { "remote-endpoint", "\\_SB.PCI0.I2C2.CAM0.EP00" }, } }) } diff --git a/Documentation/firmware-guide/acpi/dsd/leds.rst b/Documentation/firmware-guide/acpi/dsd/leds.rst index 93db592c93c7..a97cd07d49be 100644 --- a/Documentation/firmware-guide/acpi/dsd/leds.rst +++ b/Documentation/firmware-guide/acpi/dsd/leds.rst @@ -15,11 +15,6 @@ Referring to LEDs in Device tree is documented in [video-interfaces], in "flash-leds" property documentation. In short, LEDs are directly referred to by using phandles. -While Device tree allows referring to any node in the tree [devicetree], in -ACPI references are limited to device nodes only [acpi]. For this reason using -the same mechanism on ACPI is not possible. A mechanism to refer to non-device -ACPI nodes is documented in [data-node-ref]. - ACPI allows (as does DT) using integer arguments after the reference. A combination of the LED driver device reference and an integer argument, referring to the "reg" property of the relevant LED, is used to identify @@ -74,7 +69,7 @@ omitted. :: Package () { Package () { "flash-leds", - Package () { ^LED, "led@0", ^LED, "led@1" }, + Package () { "^LED.LED0", "^LED.LED1" }, } } }) diff --git a/Documentation/gpu/xe/index.rst b/Documentation/gpu/xe/index.rst index 3f07aa3b5432..89bbdcccf8eb 100644 --- a/Documentation/gpu/xe/index.rst +++ b/Documentation/gpu/xe/index.rst @@ -16,6 +16,7 @@ DG2, etc is provided to prototype the driver. xe_migrate xe_cs xe_pm + xe_gt_freq xe_pcode xe_gt_mcr xe_wa diff --git a/Documentation/gpu/xe/xe_gt_freq.rst b/Documentation/gpu/xe/xe_gt_freq.rst new file mode 100644 index 000000000000..c0811200e327 --- /dev/null +++ b/Documentation/gpu/xe/xe_gt_freq.rst @@ -0,0 +1,14 @@ +.. SPDX-License-Identifier: (GPL-2.0+ OR MIT) + +========================== +Xe GT Frequency Management +========================== + +.. kernel-doc:: drivers/gpu/drm/xe/xe_gt_freq.c + :doc: Xe GT Frequency Management + +Internal API +============ + +.. kernel-doc:: drivers/gpu/drm/xe/xe_gt_freq.c + :internal: diff --git a/Documentation/hwmon/dell-smm-hwmon.rst b/Documentation/hwmon/dell-smm-hwmon.rst index 74905675d71f..5a4edb6565cf 100644 --- a/Documentation/hwmon/dell-smm-hwmon.rst +++ b/Documentation/hwmon/dell-smm-hwmon.rst @@ -32,12 +32,12 @@ Temperature sensors and fans can be queried and set via the standard =============================== ======= ======================================= Name Perm Description =============================== ======= ======================================= -fan[1-3]_input RO Fan speed in RPM. -fan[1-3]_label RO Fan label. -fan[1-3]_min RO Minimal Fan speed in RPM -fan[1-3]_max RO Maximal Fan speed in RPM -fan[1-3]_target RO Expected Fan speed in RPM -pwm[1-3] RW Control the fan PWM duty-cycle. +fan[1-4]_input RO Fan speed in RPM. +fan[1-4]_label RO Fan label. +fan[1-4]_min RO Minimal Fan speed in RPM +fan[1-4]_max RO Maximal Fan speed in RPM +fan[1-4]_target RO Expected Fan speed in RPM +pwm[1-4] RW Control the fan PWM duty-cycle. pwm1_enable WO Enable or disable automatic BIOS fan control (not supported on all laptops, see below for details). @@ -93,7 +93,7 @@ Again, when you find new codes, we'd be happy to have your patches! --------------------------- The driver also exports the fans as thermal cooling devices with -``type`` set to ``dell-smm-fan[1-3]``. This allows for easy fan control +``type`` set to ``dell-smm-fan[1-4]``. This allows for easy fan control using one of the thermal governors. Module parameters diff --git a/Documentation/kbuild/makefiles.rst b/Documentation/kbuild/makefiles.rst index 7964e0c245ae..81607ce40759 100644 --- a/Documentation/kbuild/makefiles.rst +++ b/Documentation/kbuild/makefiles.rst @@ -656,6 +656,20 @@ cc-cross-prefix endif endif +$(RUSTC) support functions +-------------------------- + +rustc-min-version + rustc-min-version tests if the value of $(CONFIG_RUSTC_VERSION) is greater + than or equal to the provided value and evaluates to y if so. + + Example:: + + rustflags-$(call rustc-min-version, 108500) := -Cfoo + + In this example, rustflags-y will be assigned the value -Cfoo if + $(CONFIG_RUSTC_VERSION) is >= 1.85.0. + $(LD) support functions ----------------------- diff --git a/Documentation/netlink/specs/ovs_vport.yaml b/Documentation/netlink/specs/ovs_vport.yaml index 86ba9ac2a521..b538bb99ee9b 100644 --- a/Documentation/netlink/specs/ovs_vport.yaml +++ b/Documentation/netlink/specs/ovs_vport.yaml @@ -123,12 +123,12 @@ attribute-sets: operations: name-prefix: ovs-vport-cmd- + fixed-header: ovs-header list: - name: new doc: Create a new OVS vport attribute-set: vport - fixed-header: ovs-header do: request: attributes: @@ -141,7 +141,6 @@ operations: name: del doc: Delete existing OVS vport from a data path attribute-set: vport - fixed-header: ovs-header do: request: attributes: @@ -152,7 +151,6 @@ operations: name: get doc: Get / dump OVS vport configuration and state attribute-set: vport - fixed-header: ovs-header do: &vport-get-op request: attributes: diff --git a/Documentation/netlink/specs/rt_link.yaml b/Documentation/netlink/specs/rt_link.yaml index 0c4d5d40cae9..a048fc30389d 100644 --- a/Documentation/netlink/specs/rt_link.yaml +++ b/Documentation/netlink/specs/rt_link.yaml @@ -1094,11 +1094,10 @@ attribute-sets: - name: prop-list type: nest - nested-attributes: link-attrs + nested-attributes: prop-list-link-attrs - name: alt-ifname type: string - multi-attr: true - name: perm-address type: binary @@ -1138,6 +1137,13 @@ attribute-sets: type: nest nested-attributes: link-dpll-pin-attrs - + name: prop-list-link-attrs + subset-of: link-attrs + attributes: + - + name: alt-ifname + multi-attr: true + - name: af-spec-attrs attributes: - @@ -2071,9 +2077,10 @@ attribute-sets: type: u32 - name: mctp-attrs + name-prefix: ifla-mctp- attributes: - - name: mctp-net + name: net type: u32 - name: stats-attrs @@ -2319,7 +2326,6 @@ operations: - min-mtu - max-mtu - prop-list - - alt-ifname - perm-address - proto-down-reason - parent-dev-name diff --git a/Documentation/netlink/specs/tc.yaml b/Documentation/netlink/specs/tc.yaml index b02d59a0349c..043f205bc1ae 100644 --- a/Documentation/netlink/specs/tc.yaml +++ b/Documentation/netlink/specs/tc.yaml @@ -227,7 +227,7 @@ definitions: type: u8 doc: log(P_max / (qth-max - qth-min)) - - name: Scell_log + name: Scell-log type: u8 doc: cell size for idle damping - @@ -248,7 +248,7 @@ definitions: name: DPs type: u32 - - name: def_DP + name: def-DP type: u32 - name: grio @@ -2017,7 +2017,8 @@ attribute-sets: attributes: - name: act - type: nest + type: indexed-array + sub-type: nest nested-attributes: tc-act-attrs - name: police @@ -2250,7 +2251,8 @@ attribute-sets: attributes: - name: act - type: nest + type: indexed-array + sub-type: nest nested-attributes: tc-act-attrs - name: police @@ -2745,7 +2747,7 @@ attribute-sets: type: u16 byte-order: big-endian - - name: key-l2-tpv3-sid + name: key-l2tpv3-sid type: u32 byte-order: big-endian - @@ -3504,7 +3506,7 @@ attribute-sets: name: rate64 type: u64 - - name: prate4 + name: prate64 type: u64 - name: burst diff --git a/Documentation/rust/coding-guidelines.rst b/Documentation/rust/coding-guidelines.rst index 329b070a1d47..a2e326b42410 100644 --- a/Documentation/rust/coding-guidelines.rst +++ b/Documentation/rust/coding-guidelines.rst @@ -227,3 +227,149 @@ The equivalent in Rust may look like (ignoring documentation): That is, the equivalent of ``GPIO_LINE_DIRECTION_IN`` would be referred to as ``gpio::LineDirection::In``. In particular, it should not be named ``gpio::gpio_line_direction::GPIO_LINE_DIRECTION_IN``. + + +Lints +----- + +In Rust, it is possible to ``allow`` particular warnings (diagnostics, lints) +locally, making the compiler ignore instances of a given warning within a given +function, module, block, etc. + +It is similar to ``#pragma GCC diagnostic push`` + ``ignored`` + ``pop`` in C +[#]_: + +.. code-block:: c + + #pragma GCC diagnostic push + #pragma GCC diagnostic ignored "-Wunused-function" + static void f(void) {} + #pragma GCC diagnostic pop + +.. [#] In this particular case, the kernel's ``__{always,maybe}_unused`` + attributes (C23's ``[[maybe_unused]]``) may be used; however, the example + is meant to reflect the equivalent lint in Rust discussed afterwards. + +But way less verbose: + +.. code-block:: rust + + #[allow(dead_code)] + fn f() {} + +By that virtue, it makes it possible to comfortably enable more diagnostics by +default (i.e. outside ``W=`` levels). In particular, those that may have some +false positives but that are otherwise quite useful to keep enabled to catch +potential mistakes. + +On top of that, Rust provides the ``expect`` attribute which takes this further. +It makes the compiler warn if the warning was not produced. For instance, the +following will ensure that, when ``f()`` is called somewhere, we will have to +remove the attribute: + +.. code-block:: rust + + #[expect(dead_code)] + fn f() {} + +If we do not, we get a warning from the compiler:: + + warning: this lint expectation is unfulfilled + --> x.rs:3:10 + | + 3 | #[expect(dead_code)] + | ^^^^^^^^^ + | + = note: `#[warn(unfulfilled_lint_expectations)]` on by default + +This means that ``expect``\ s do not get forgotten when they are not needed, which +may happen in several situations, e.g.: + +- Temporary attributes added while developing. + +- Improvements in lints in the compiler, Clippy or custom tools which may + remove a false positive. + +- When the lint is not needed anymore because it was expected that it would be + removed at some point, such as the ``dead_code`` example above. + +It also increases the visibility of the remaining ``allow``\ s and reduces the +chance of misapplying one. + +Thus prefer ``expect`` over ``allow`` unless: + +- Conditional compilation triggers the warning in some cases but not others. + + If there are only a few cases where the warning triggers (or does not + trigger) compared to the total number of cases, then one may consider using + a conditional ``expect`` (i.e. ``cfg_attr(..., expect(...))``). Otherwise, + it is likely simpler to just use ``allow``. + +- Inside macros, when the different invocations may create expanded code that + triggers the warning in some cases but not in others. + +- When code may trigger a warning for some architectures but not others, such + as an ``as`` cast to a C FFI type. + +As a more developed example, consider for instance this program: + +.. code-block:: rust + + fn g() {} + + fn main() { + #[cfg(CONFIG_X)] + g(); + } + +Here, function ``g()`` is dead code if ``CONFIG_X`` is not set. Can we use +``expect`` here? + +.. code-block:: rust + + #[expect(dead_code)] + fn g() {} + + fn main() { + #[cfg(CONFIG_X)] + g(); + } + +This would emit a lint if ``CONFIG_X`` is set, since it is not dead code in that +configuration. Therefore, in cases like this, we cannot use ``expect`` as-is. + +A simple possibility is using ``allow``: + +.. code-block:: rust + + #[allow(dead_code)] + fn g() {} + + fn main() { + #[cfg(CONFIG_X)] + g(); + } + +An alternative would be using a conditional ``expect``: + +.. code-block:: rust + + #[cfg_attr(not(CONFIG_X), expect(dead_code))] + fn g() {} + + fn main() { + #[cfg(CONFIG_X)] + g(); + } + +This would ensure that, if someone introduces another call to ``g()`` somewhere +(e.g. unconditionally), then it would be spotted that it is not dead code +anymore. However, the ``cfg_attr`` is more complex than a simple ``allow``. + +Therefore, it is likely that it is not worth using conditional ``expect``\ s when +more than one or two configurations are involved or when the lint may be +triggered due to non-local changes (such as ``dead_code``). + +For more information about diagnostics in Rust, please see: + + https://doc.rust-lang.org/stable/reference/attributes/diagnostics.html diff --git a/Documentation/rust/quick-start.rst b/Documentation/rust/quick-start.rst index 2d107982c87b..ded0d0836aee 100644 --- a/Documentation/rust/quick-start.rst +++ b/Documentation/rust/quick-start.rst @@ -128,7 +128,7 @@ Rust standard library source **************************** The Rust standard library source is required because the build system will -cross-compile ``core`` and ``alloc``. +cross-compile ``core``. If ``rustup`` is being used, run:: diff --git a/Documentation/wmi/devices/msi-wmi-platform.rst b/Documentation/wmi/devices/msi-wmi-platform.rst index 31a136942892..73197b31926a 100644 --- a/Documentation/wmi/devices/msi-wmi-platform.rst +++ b/Documentation/wmi/devices/msi-wmi-platform.rst @@ -138,6 +138,10 @@ input data, the meaning of which depends on the subfeature being accessed. The output buffer contains a single byte which signals success or failure (``0x00`` on failure) and 31 bytes of output data, the meaning if which depends on the subfeature being accessed. +.. note:: + The ACPI control method responsible for handling the WMI method calls is not thread-safe. + This is a firmware bug that needs to be handled inside the driver itself. + WMI method Get_EC() ------------------- |